The present invention relates to an oil pan baffle plate and, more particularly, to an oil pan baffle plate that more effectively removes air from engine lubricating oil return dropping thereon so that lubricating performance of the oil is not diminished.
FIG. 7 is an overall view of a conventional automobile engine 1, and FIGS. 8-10 show an oil pan 2 that attaches to the lower part of engine 1. Oil pan 2 is filled with a pool of lubricating oil 3 from which oil is supplied in known manner to the engine 1 for providing a lubricating film of oil between sliding friction parts in the engine 1 thereby avoiding direct contact between one metal part and another so that wear between the two is prevented. Reference numeral 3a in FIG. 7 denotes the surface of the pool of oil.
Supply of oil from the pool is drawn up through oil strainer 4 to the engine, lubricates various parts including crankshaft 6 and connecting rod 7 inside cylinder block 5 and cam shaft 9 inside cylinder head 8, discharging therefrom inside engine 1, and returns to oil pan 2 from the upper part of the engine by the force of gravity.
Oil 3 that is discharged into engine 1 falls to the bottom of engine 1 and onto baffle plate 10 in oil pan 2. Because the oil 3 that descends onto baffle plate 10 contains a large quantity of mixed-in air, if it flows into oil pan 2 in this state, there is concern that it will be drawn up through oil strainer 4 and air presence therein will result in poor lubrication of engine parts. For that reason the air is removed before it is drawn into oil strainer 4.
As shown in FIGS. 7 and 8, the baffle plate 10 in the short direction thereof (i.e., the direction of line A--A in FIG. 9 and viewing the oil pan 2 from the front) only of baffle is curved so as to bulge upward, so that oil 3 falling on the upper surface of baffle plate 10 conveys or travels to the walls on both sides (horizontally, in FIG. 9) of oil pan 2. During that travel, air will remove from the oil before it flows down into the pool of oil 3.
As seen from FIG. 10, the long direction of oil pan 2 has a shallow-bottom part 2A and a deep-bottom part 2B, so that oil 3 that seeps into oil pan 2 from gap 2C between oil pan 2 and baffle plate 10 (FIG. 9) loses its air as it flows along the shallow-bottom part 2A. Also, as shown in FIG. 10, the baffle plate 10, in its long direction, is not curved but rather, is straight.
Reference numeral 11 in FIG. 9, denotes an opening in baffle plate 10 through which oil strainer 4 is received, and around the rim of this opening 11 is a flange 11a that keeps oil 3 from flowing through the opening. Plural oil dropping holes 12 are provided in the baffle plate 10. The oil dropping hole 12 that communicates with opening 11 also serves as a pass through hole for pipe 4a of oil strainer 4 (see FIG. 7).
Again referring to FIG. 9, reference numeral 13 denotes beads on baffle plate 10, reference numeral 14 denotes attachment bolt holes in flange 15 of oil pan 2 for attachment to cylinder block 5, and reference numeral 15a denotes an insertion hole for an oil level gauge. In FIG. 10, 10a is a flange on the outer rim of baffle plate 10.
In the prior art described above, baffle plate 10 in oil pan 2 is shaped with a curve so that the short direction of oil pan 2 projects upward, while it is not curved in its long direction. This creates the problem that the oil 3 that falls from above flows easily in the short direction but not in the long direction.
This creates the problem that oil 3 does not flow fully to the inner wall around oil pan 2, and oil 3 that does not flow fully to the inner wall around the oil pan 2 falls through opening 11 at the oil strainer 4 into the oil pool 3 with air still mixed in, and when oil is drawn through strainer 4 taking along the air mixed in, poor lubrication results.
Another problem is that when a load is applied to oil pan 2 in either the tensile direction (see FIG. 11) or the compression direction, the side curved in the short direction is easily deformed, while it is not easily deformed in the long direction. That is, the problem is that the baffle plate 10 can withstand a load in its short direction but not a load in its long direction, and it will crack as shown by symbol C in FIG. 12.
An engine bearing cap is disclosed in Japanese published utility model application HEI 1-113116 1989! which supports a crankshaft, is joined to the lower side of the engine block. Formed integrally with said bearing cap for each air tube is a baffle plate having a shape that is curved along the rotation path of a connecting rod, etc. between the bearings of this bearing cap, and oil return holes are provided in the upper part of each curved part of the baffle plate.
The baffle plate of the utility model application has a curved shape between the bearings of the bearing cap that supports the crankshaft. The baffle plate is formed integrally with the bearing cap, but because the baffle plate is shaped with a curve that follows the path of rotation of the connecting rod, etc., the baffle plate is curved only in the direction of one side of the oil pan (the direction of the rotation path). Therefore there is no shape curved toward the other side, and if a load is applied in the other direction, there is concern that the baffle plate, being unable to deform, will crack.